Defending against one possible flaw in original() which isn't currently a problem but may become so.

eventlet/patcher.py

@@ -151,6 +151,10 @@ def _original_patch_function(func, *module_names):
 def original(modname):
     """ This returns an unpatched version of a module; this is useful for 
     Eventlet itself (i.e. tpool)."""
+    # note that it's not necessary to temporarily install unpatched
+    # versions of all patchable modules during the import of the
+    # module; this is because none of them import each other, except
+    # for threading which imports thread
     original_name = '__original_module_' + modname
     if original_name in sys.modules:
         return sys.modules.get(original_name)
@@ -159,6 +163,11 @@ def original(modname):
     # dict; be sure to restore whatever module had that name already
     saver = SysModulesSaver((modname,))
     sys.modules.pop(modname, None)
+    # install original thread module if we're getting the original
+    # threading module
+    if modname == 'threading':
+        saver.save('thread')
+        sys.modules['thread'] = original('thread')
     try:
         real_mod = __import__(modname, {}, {}, modname.split('.')[:-1])
         # hacky hack: Queue's constructor imports threading; therefore